Zara Phillips delivered a stunning performance in front of 50,000 people on her Olympics cross-country debut at Greenwich Park on Monday to keep Great Britain firmly in medal contention.

The Queen's granddaughter was watched from the main arena stands by the Duke and Duchess of Cambridge, Prince Harry and the Duchess of Cornwall – and she did not disappoint her audience.

The 31-year-old former world champion produced a clear round inside the time, completing a course that claimed its fair share of casualties.

Her team-mate Nicola Wilson also went clear inside the time aboard Opposition Buzz, while 51-year-old Mary King collected just 1.2 time penalties on Imperial Cavalier.

Kristina Cook, the team's fourth rider, then produced a fine round and Britain finished the day in the silver medal position for the team event, behind Germany.

William Fox-Pitt collected 9.2 time faults aboard Lionheart to go 22nd, to leave the British scores of Cook, King and Phillips as the counting ones after cross-country.

Germany lead the team competition on 124.70 penalties, with Britain in second [130.20] and Sweden third [131.40]. There is a tie for the individual lead between Germany's Ingrid Klimke and Swedish rider Sara Algotsson Ostholt, with 56-year-old double Olympic champion Mark Todd third.

Cook is the best of the British riders in fifth, with King sixth, Phillips equal 10th, Wilson 20th and Fox-Pitt 22nd.